serial: Rename SERIAL_SUPPORT to SERIAL

Rename these options so that CONFIG_IS_ENABLED can be used with them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/mips/mach-mtmips/mt7628/Kconfig b/arch/mips/mach-mtmips/mt7628/Kconfig
index b25b20f..f451c15 100644
--- a/arch/mips/mach-mtmips/mt7628/Kconfig
+++ b/arch/mips/mach-mtmips/mt7628/Kconfig
@@ -29,7 +29,7 @@
 
 config BOARD_VOCORE2
 	bool "VoCore2"
-	select SPL_SERIAL_SUPPORT
+	select SPL_SERIAL
 	select SPL_UART2_SPIS_PINMUX
 	help
 	  VoCore VoCore2 board has a MT7628 SoC with 128 MiB of RAM
@@ -39,7 +39,7 @@
 
 config SPL_UART2_SPIS_PINMUX
 	bool "Use alternative pinmux for UART2 in SPL stage"
-	depends on SPL_SERIAL_SUPPORT
+	depends on SPL_SERIAL
 	help
 	  Select this if the UART2 of your board is connected to GPIO 16/17
 	  (shared with SPIS) rather than the usual GPIO 20/21.